As I write this, the Texas Rangers are on the verge of winning their first World Series title. Most fans and analysts focus on their potent offensive attack and rightfully so. In terms of depth, we haven't seen an offense this good in quite some time. Their pitching has been solid as well without the benefit of an established ace.
When people look back, they may throw that tag on C.J. Wilson, but the long and short of it is that superior fielding can be cited for making those pitchers look good. In particular, the infield may be the best defensive unit in baseball.
Defensive Efficiency Ratio: .704 (5th)
Runs allowed per nine innings: 677 (13th)
Fielding Percentage: .981 (27th)
Baseball Reference: +24 runs (9th)
Fangraphs: +25.9 runs (6th)
Fielding Bible: +44 runs (4th)
Baseball Prospectus: +22.6 (2nd)
Composite Runs: +29.2 runs
The Rangers are exhibit A for how looking at errors and fielding percentage to measure defensive efficiency will get you nowhere. It's about the number of balls you get to and not the balls you kick. Slow teams have great fielding percentages because they don't get to the tough plays.
If I could categorize all of the comments from this series, I would put errors and fielding percentage on top. Usually, the response is in regards to a favorite player I somehow dogged. His fielding percentage is good, so he must be a good fielder. In one particular case, a fan cited his guy as having a 1.000 fielding percentage. That's great but it has very little to do with who is actually good at fielding.
Others have cited range factor, which is a good crude number, but it has its pitfalls. The primary pitfall is that it doesn't adjust for particular tendencies of a pitching staff. If you have a fly ball staff, the outfielders are going to look like the second coming of Willie Mays. The same is true of infielders and a ground ball staff. The unfortunate thing is that the opposite is also true— a fielder can look bad simply because he doesn't get as many opportunities.
Ian Kinsler's numbers are off the charts good. If we combine the four metrics used above, Kinsler leads all second baseman with a combined 50.9 runs above average. In order for that stat to be meaningful you would need to divide it by four, but that is remarkable no matter how you express it. Watch—he won't win a Gold Glove.
Mitch Moreland is barely hanging onto his job as it is. Simply put, the Rangers have too many good hitters to fit them all into a lineup. Moreland sometimes finds himself on the bench in place of Mike Napoli. The fact that he finished near the bottom of the AL in fielding according to these four metrics is not helping.
There will be some movement within the roster depending on who is hot, but you will see the same group of guys coming back.
There is no reason to believe that the Rangers won't be this good again. The majority of their fielders have an excellent pedigree and they are all young enough to continue at top form.